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DOI: 10.1055/s-0032-1320355
Effect of light intensity on chemical composition and essential oil content in Piper aduncum L. leaves and roots
This study aims to evaluate the content, yield and quality of Piper aduncum leaves and roots essential oil (EO) under different conditions of Photosynthetically Active Radiation (PAR). The experimental design was completely randomized with three treatments and seven replicates of five plants each. The treatments were three levels of shading: 0% (1661±180), 50% (1089±118) and 70% (598±52µ mol m-2 s-1 PAR). The content and yield of EO leaves did not differ by Tukey test at 5% of significance level, but the Principal Components Analysis (PCA) showed different ratios of the constituents among treatments. The compounds of leaves EO with higher relative percentage (RP), asaricin and safrole, showed a strong relation with 70 and 50% of shading, respectively, while α-humulene was related to the light and spathulenol had no effect on the light conditions. In the roots asaricin and safrole had a higher RP than in leaves and a strong correlation to 50% of shading and full sunlight, respectively, whereas guaiol showed a strong relation to 70% of shading. The EO content of the roots did not differ, however, higher EO yield was observed in full sunlight plants, which also had greater root biomass.